One purpose of the project is to complete the genetic analysis of this mutant in the mouse, including linkage information and extent of modifying genes, and thus variations in expressivity, coming from certain crosses. Another purpose is to continue the investigation of teratological agents on the development of anophthalmia, especially around the time period of 9 to 10 days post-coitus when the optic vesicle is forming the optic cup or failing by degrees to do so. Although complete bilateral anophthalmia is characteristic of 90 percent of the inbred strain and thus considerably more extreme in expression than occurs in human beings, there are microphthalmic expressions that parallel very closely microphthalmia in man in the other 10 percent and especially from certain crosses.